Lifting jack



April 10, 1928.

. A. C. HOPKINS LIFTING JACK Filed March 26; 1927 INVENTOR ifi/kw [ifif/gklks WA WORN/5m Patented Apr. 10, 1928 oNi-rsb; start masses 1 ARTHUR c. Horxm'sfor nines, MIcHIeAim AssIeivoR r NATIONAL STANDARD "commun on NILES, MICHIGAN] I LIF'IING JACK.

Application mean-arenas, 1927. Seria1'No,178,58 8. 1

' The'main object of this invention is to provide animprovedlifting jack of the screw type which is very compact when collapsed and of considerable height when fully extended, and onein which the parts are so arranged that they may be easilyextended and collapsed' Objects pertaining to details and economies of the invention will'definitely appear from the detailed description to follow. The invention is defined in the claims.

A structure embodying-the features of my inventionis clearly'illustrated in the accompahdying'" drawing forming application, in which:

' L'Fig. l is a side elevation of a structure embodying the featuresrof my invention.

1 Fig.2 is a detail view mainly in vertical section on line-22 of F ig; 1.

Fig. 3 is a horizontal section on a line corresponding to line 3"3,.ofFigs. 1, 2 and 5.

Fig. 4 is'a detail view mainly in horizontal section online 44: of Figs. 1, 2 and 5. Fig. 5 is a diagrammatic view showlng the spiral control groove of the standard extended.

In the embodiment illustrated my improved jack comprises a standard 1 provided with a suitable base 2. The standard 1. has a longitudinal bore 3 therein with a spiral groove 1 extending from end to end thereof, this groove terminating in horizontal extensions 5, the outer or end walls 6 of WhlCh are beveled or inclined.

a The tubular lifting member 7 is'adapted to telescope in the bore 3 and is externally threaded. The standard 1 is provided with a yoke-like bracket 8 at its upper end which has an opening '9- alined with the bore of the standard. The nut 10 hasthreaded engagement with the member 7 and is supported on the end of the standard by the thrust bearing 11. This nut has a beveled gear 12 with whichthe driving gear 13 meshes, this driving gear being mounted on the bracket 8' and having ahub adapted to receive the handle 14 by meansof which the gear 13 is rotated. V As the lifting member 7 is raised and lowered by the rotation of thenut it is rotated within the standard by means of the pin 15 engaging the spiral groove 4. This pin is arranged ina radially disposed holder 16, a coiled spring 17 yieldingly supportlng the pm.

a part of' this when the lifting member is raised, be lowered to bring the pin 15 into the fhorizontal plane of the groove 'extensions'figthe member 7 may bexrotat'ed'in onerdirection.

with the nut as a unit, the pinconstituting' 'a stop limiting the upwardltravel of [the lifting member, while the split ring 18on the 7 itsupward and downward travel, thereby preventingifsetting. of'these parts;that;is,

there is'apositive differential .movement and theffriction.. is. very materiallyreduced. Y

. VVhe'n the liftinginember 7 is at-the ends of its stroke the pinl5= readily passeslup the inclined walls-6 of the groove, allowing rota tion of the nut and lifting member as a unit inone direction. However, as soon as this;

rotation is reversed the pin engages the spiral'wall 21 of the groove opposite the inclined end 6, guiding the pin intothe groove andcontrolling the rotation "of the lifting member 7 throughout itstravel. The lift: ing member 19 is free to rotate until its head engages the work and, it being held against rotation, the member 7 acts asa driving nut for the member 19.

My improved lifting jack very simple and economical in structure, and'at the same time is durable and easy to operate. c Having thus described my invention what I claim as new and desire to ters Patent is; c

1. In a lifting jack, the combination of a internal spiral groovetherein terminating at its ends in oppositely disposed horizontal extensions having beveled end walls, said standard being provided with a yoke-like secure by Let-' brackethaving a part disposedQin spaced relation to the, upper end of the standard with an opening therein alined with said bore, a nut interposed between said bracket and standard and provided with a gear, a thrust bearing disposed between the nut and the end of the standard, a driving gear' mounted on said bracket coacting with said gear on said nut, a tubular; lifting member disposed in said standard and externally 95 standard-having a longitudinal bore with an threaded to .c oact with said nut, a t-stop on the upper end of said lifting member coact ing with the bracket to limit its downward travel ,,.a.;yieldingly supported pin disposed radially in'said liftingmemberiand ooact- -ing with said spiral groove to rotate said lifting member durin its longitudinal tr a- '7 vel underthe action 0 said nutrand yielding to permit the rotation of .saidiifting meme her and nut as a unit in one direction when the :pin is inthe horizontal plane of one of saidf'grobveiex'tensions, andla second lifting member disposed 7 within 7 and having threaded engagerrient[with'v said tubular lifting member and provided with a head.

Inga lifting jack, the combination of a standard ihavi'ng a longitudinal bore with an internal spiral "g=.roove therein terminating at its ends' iniojppositely disposedhorizontal extensions having beveled end walls, a driven mrt mounted on the upper end :ofsaid 1 standard,pa tubularliftingmember disposed V in said standard and'externalliy threadedto coact-with said-nut, astop on the upper end of saidlliifti-ng {member cblacting with the bracket to limit its downward travel, a

yield-ingly supportedpin disposed radiall i said spiral groove to rotate said wit 7 :fting member during itsiongitudinal travel under in' said liiting member and eoaeting 1 the aotion of saidlnutand yi'eidingto per.

' my hand.

m-it the rotationofsaid liftingmember and nut .as a unit in one-direction when the pin s in the horlzontal plane of one of saidgroove extensions, and a second liftingmemher disposed within and having threaded V engagement with said tubular lifting memher and provided with a head. 7

'3. In a lifting jack, the combination of a standard hayinga longitudinal bore 'with'an internal spiral groove therein, a nut rota-tably mounted on said standard and provided 7 with a gear, a1driving gear mounted on said standard coasting with said g'ear on 'said tatesaid lifting member during its long-itua dinal travel underl-thje action of said nut and yieldingatopermit the rotation of said liaft ing member and-nut as a unit invone direo tion when the pin is in the horizontal '{planes' 7 of the ends of said groove, and, :a second lift ing member disposed within and having threaded engagement withsaiditdbular lifting memzber and provided with a head.

7 In witness whereof Ihavle hereunto set imam. HOPKINS. 

